From 84c3b1e340da9976741d18132bd53f738b74295c Mon Sep 17 00:00:00 2001
From: Jan Vorlicek <janvorli@microsoft.com>
Date: Wed, 15 Dec 2021 00:54:07 +0100
Subject: [PATCH] Unify the FlushProcessWriteBuffers mechanism for macOS arm64
 / x64

The macOS arm64 was using a new mechanism to implement FlushProcessWriteBuffers
because the original one based on a wired memory page doesn't work on arm64.
We have seen people hitting problems with the wired memory page allocation on
x64 in the past due to the fact that wired memory is a scarce resource and
in some cases, e.g. in presence of apps that greedily grab all of the available
wired memory pages, we were unable to initialize coreclr and execute any .NET
application.

This change switches x64 to the same mechanism as arm64 to prevent that issue
from happening and updates the minimum supported x64 macOS to 10.14. That's the
version required for the new APIs the change is using. Apple stopped supporting
10.13 a year ago anyways.
---
 eng/native/configurecompiler.cmake     |  2 +-
 src/coreclr/gc/unix/gcenv.unix.cpp     | 10 ++++------
 src/coreclr/pal/src/thread/process.cpp | 10 ++++------
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/eng/native/configurecompiler.cmake b/eng/native/configurecompiler.cmake
index c22469f567b726..650ccaecac213b 100644
--- a/eng/native/configurecompiler.cmake
+++ b/eng/native/configurecompiler.cmake
@@ -417,7 +417,7 @@ if (CLR_CMAKE_HOST_UNIX)
         set(CMAKE_OSX_DEPLOYMENT_TARGET "11.0")
         add_compile_options(-arch arm64)
       elseif(CLR_CMAKE_HOST_ARCH_AMD64)
-        set(CMAKE_OSX_DEPLOYMENT_TARGET "10.13")
+      set(CMAKE_OSX_DEPLOYMENT_TARGET "10.14")
         add_compile_options(-arch x86_64)
       else()
         clr_unknown_arch()
diff --git a/src/coreclr/gc/unix/gcenv.unix.cpp b/src/coreclr/gc/unix/gcenv.unix.cpp
index 2a37c17f8c9f81..6319c519727e73 100644
--- a/src/coreclr/gc/unix/gcenv.unix.cpp
+++ b/src/coreclr/gc/unix/gcenv.unix.cpp
@@ -67,7 +67,6 @@
 #include <mach/mach_port.h>
 #include <mach/mach_host.h>
 
-#if defined(HOST_ARM64)
 #include <mach/task.h>
 #include <mach/vm_map.h>
 extern "C"
@@ -84,7 +83,6 @@ extern "C"
             abort();                                                        \
         }                                                                   \
     } while (false)
-#endif // defined(HOST_ARM64)
 
 #endif // __APPLE__
 
@@ -372,7 +370,7 @@ bool GCToOSInterface::Initialize()
     {
         s_flushUsingMemBarrier = TRUE;
     }
-#if !(defined(TARGET_OSX) && defined(HOST_ARM64))
+#ifndef TARGET_OSX
     else
     {
         assert(g_helperPage == 0);
@@ -404,7 +402,7 @@ bool GCToOSInterface::Initialize()
             return false;
         }
     }
-#endif // !(defined(TARGET_OSX) && defined(HOST_ARM64))
+#endif // !TARGET_OSX
 
     InitializeCGroup();
 
@@ -544,7 +542,7 @@ void GCToOSInterface::FlushProcessWriteBuffers()
         status = pthread_mutex_unlock(&g_flushProcessWriteBuffersMutex);
         assert(status == 0 && "Failed to unlock the flushProcessWriteBuffersMutex lock");
     }
-#if defined(TARGET_OSX) && defined(HOST_ARM64)
+#ifdef TARGET_OSX
     else
     {
         mach_msg_type_number_t cThreads;
@@ -570,7 +568,7 @@ void GCToOSInterface::FlushProcessWriteBuffers()
         machret = vm_deallocate(mach_task_self(), (vm_address_t)pThreads, cThreads * sizeof(thread_act_t));
         CHECK_MACH("vm_deallocate()", machret);
     }
-#endif // defined(TARGET_OSX) && defined(HOST_ARM64)
+#endif // TARGET_OSX
 }
 
 // Break into a debugger. Uses a compiler intrinsic if one is available,
diff --git a/src/coreclr/pal/src/thread/process.cpp b/src/coreclr/pal/src/thread/process.cpp
index 2b349a6c37b1c2..f31449fb19c3e8 100644
--- a/src/coreclr/pal/src/thread/process.cpp
+++ b/src/coreclr/pal/src/thread/process.cpp
@@ -85,7 +85,6 @@ SET_DEFAULT_DEBUG_CHANNEL(PROCESS); // some headers have code with asserts, so d
 #include <libproc.h>
 #include <sys/sysctl.h>
 #include <sys/posix_sem.h>
-#if defined(HOST_ARM64)
 #include <mach/task.h>
 #include <mach/vm_map.h>
 extern "C"
@@ -103,7 +102,6 @@ extern "C"
         }                                                                   \
     } while (false)
 
-#endif // defined(HOST_ARM64)
 #endif // __APPLE__
 
 #ifdef __NetBSD__
@@ -3472,7 +3470,7 @@ InitializeFlushProcessWriteBuffers()
         }
     }
 
-#if defined(TARGET_OSX) && defined(HOST_ARM64)
+#ifdef TARGET_OSX
     return TRUE;
 #else
     s_helperPage = static_cast<int*>(mmap(0, GetVirtualPageSize(), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0));
@@ -3502,7 +3500,7 @@ InitializeFlushProcessWriteBuffers()
     }
 
     return status == 0;
-#endif // defined(TARGET_OSX) && defined(HOST_ARM64)
+#endif // TARGET_OSX
 }
 
 #define FATAL_ASSERT(e, msg) \
@@ -3552,7 +3550,7 @@ FlushProcessWriteBuffers()
         status = pthread_mutex_unlock(&flushProcessWriteBuffersMutex);
         FATAL_ASSERT(status == 0, "Failed to unlock the flushProcessWriteBuffersMutex lock");
     }
-#if defined(TARGET_OSX) && defined(HOST_ARM64)
+#ifdef TARGET_OSX
     else
     {
         mach_msg_type_number_t cThreads;
@@ -3578,7 +3576,7 @@ FlushProcessWriteBuffers()
         machret = vm_deallocate(mach_task_self(), (vm_address_t)pThreads, cThreads * sizeof(thread_act_t));
         CHECK_MACH("vm_deallocate()", machret);
     }
-#endif // defined(TARGET_OSX) && defined(HOST_ARM64)
+#endif // TARGET_OSX
 }
 
 /*++